Fuel cut-off device for fuel injection system



Aug.- 18, 1959 E. oLsoN ETAL FUEL CUT-oFF DEVICE FoR FUEL INJECTIONSYSTEM Filed March 25, 1957 2 Sheets-Sheet l ATTORNEY ited Staes FUELCUT-OFF DEVICE FOR FUEL INJECTION l SYSTEM Elmer Olson, Ellsworth A.Kehoe, and Lawrence C. Derrnond, Rochester, N.Y., assignors to GeneralMotors Aatent Oilice Corporation, Detroit, Mich., a corporation of Dela-The present device relates to a fuel control device for a fuel injectionsystem and more particularly a device in which fuel flow to the enginescylinders s 'interrupted during certain decelerating conditions.

lDeceleration fuel cut-olf devices are well known but such devicesparticularly as applied to fuel injection systems have for variousreasons not functioned satisfactorily. Fuel cut-olf devices which haveutilized manifold vacuum as a fuel flow interrupting control force, asshown in Serial No. 608,797, tiled September l0, 1956, have beenparticularly trouble-some in practical applications. Manifold vacuumtype fuel cut-olf devices are designed to interrupt the fuel flow whenthe manifold vacuum reaches a given value indicative of deceleration.With the engine idling, as when in neutral, and thel throttle suddenlyopened then closed, the manifold vacuum will usually equal or exceed thevalue required to shut olf the flow of fuel with the result that theengine will stall. This same type of thing occurs when shifting asynchromesh type transmission through the various gear ratios, in thiscase, when the engine is accelerating and then the clutch depressed tochange gear ratios, the vacuum rises rapidly due to releasel of engineload causing Vthe engine to tend to stall. In the fuel cut-olf mechanismis set to functiony at a suiliciently high manifold vacuum level toavoid ythe neutral kick or ratio change stalling, as described, the fuelcut-olf mechanism wil be inetlectiveto cut off fuell flowybelow-relatively high vehicle speeds. To illustrate, a normaldeceleration fuel. cut-off device might be designed to operate on twentyinches of vacuum. During the neutral throttle kick asdesc'ribed,`manifold vacuum might easily go to twenty-three inches of vacuumactuating the fuel cut-olf device to stall the engine. Essentially, thesame phenomena would occur in changing gear ratios. If this situationwas corrected by setting the fuel cut-olf device to function at somevalue above twenty-three inches, the fuel cut-olf function would beabsent under 40 to 45 miles per hour vehicle speed since under thesespeeds manifold vacuum wouldnot be likely to reach orv exceedtwenty-three inches of vacuum. -Other devices have been .utilized todelay the actuation of the vacuum operated fuel cut-oil devices butthese additions have made the operation of the vrfuel cut-off mechanismtoo slow to give satisfactory operation.

The present device avoids the above diiculty by using a solenoidcontrolled fuel cut-olf valve rin conjunction with series connectedthrottle andVV engine speed control switches such that with the throttleclosed and the engine operating above a given speed, the solenoidv valvewill cut olf the fuel supplied to the engine cylinder. Below.' a given`vengine speed or with the throttle switch open the solenoid valve will berendered inoperative to restrictV fuelilow.l j .j I j f .1 l

In additionv to ,the novel combination of. speed and throttle switchesin controlling fuel injection fuel flow, la unique type of solenoidactuated,valve` provided. e,

lOther advantages and objectsv of the presentnvention of a manual valveis necessarily a comprise setting and is neitherl correct when theengine is hot nor when it is cold. Further, such a manual valve usuallyrequires frequent' 2,899,951 Patented Aug. 18, 1959 will be apparentfrom a perusal of the detailed description which follows.

In the drawings:

Figure l is a diagrammatic representation of a fuel injection systemembodying the subject deceleration fuel cut-oi device; and

Figures 2 and 3 are enlarged views of the solenoid control valve.

In the diagrammatic representation of Figure l, a fuel induction passageis shown generally at 12 and includes a venturi 14 posterior of which isa throttle valve 16A fuel supply source is indicated generally at 18 andin-` cludes a float controlled type valve mechanism 20, an

engine speed responsive pump 22 and a fuel metering valve generallyindicated at 24. The metering valve is under the control of a diaphragm26 through a linkage mechanism 28. The preceding elements and devicesfunction in the same manner as described in copending application646,081, filed March 14, 1957 by L. C. Derwood.

It will suffice to note that fuel is supplied to the metering valve 24by pump 22 under a pressure which is proportional to engine speed. Valve24 then delivers fuel to a distributor supply line 30 in accordance withthe actuation' of the Control mechanism 26-28 which primarily is underthe control of vacuum in passages 32 and 34. The vacuum in passage 32 isproportional to the mass of air flowing through the induction passage 12and hence causes diaphragm 26 to move valve 24 to a position increasingthe llow of fuel to line 30 as said mass air ow increases. Manifoldvacuum is available in conduit 34 when the throttle 16 is closed asdescribed in copending application Serial No. 608,797'Olson, filedSeptember l0, 1956.

An idle air bypass network is indicated generally at 44 and includes apassage l46 communicating with the induction passage anterior ofthrottle 16, a passage 48 communicating with the induction passageposteriorly of the throttle and a passage 50 interconnecting passages 46and 48. Normally a manually adjustable valve is disposed in such networkand which valve is adjusted for an average idle air flow. It is apparentthat such average adjustment adjustment due to normal engine operation.'In the present Vdevice a thermostatically controlled valve 52 isinterposedri'n passage 50 and is adapted to accurately control theidlerair ow in accordance with thervarying requirementsjof the engine asdetermined by engine temperature.

In order that the temperature responsive valve accurately reflect enginetemperature, a housing 54, Within which the thermostatically controlledvalve 52 is disposed, is

mounted upon the engine cooling'system as described in copendingapplication 650,389, led April 3, 1957v and now`Patent No. 2,848,986. Athermostat 58 is mounted i in housing '54 and iixed at one end 60 to thehousing and at theother' en d to the valve shaft 62. yIn order toprovide 4arrinitial cold running setting for the valve 52 an bypassedaround throttle valve 16 insuring sufficient air to provide lfaster thannormal engineidling speeds under cold conditions. Through thisdevice-the normal fast idle cam, which sets the throttle idling positionin accordance with engine temperatures, is eliminated. Ac-

cordingly, under idling conditions the throttle may always be closedwith the variations in the quantity of the idlingl j mixture beingcontrolled in the idle air bypass network las described.`

TVO/:secure adequate fuel enrichment when the engine is running coldadditional means are provided to supplement the normal venturi vacuumsignal acting on the upper side of metering valve control diaphragm 26.

Devices which have been used heretofore to insure an enriched startingmixture have been unsatisfactory from economy and performancestandpointssince they are active tothe same extent irregardless ofengine temperature. The result'of this' type of temperature insensitivef operation is to supply an overly enriched starting mixture to apartially warm engine wasting fuel and making engine performancesluggish. To eliminate this problem, the present device provides vacuumboost signals which are modulated in accordance'with engine temperatureand which thus preclude overenrichment of the starting mixture since thelatter is always keyed to engine temperature.

In order to provide a' metering diaphragm modulating signal a conduit 70 connects 'the metering diaphragm to a point posterior to the throttle16. In the diagrammatic disclosure of Figure l a branch 71 of conduit 70connects with idle air bypass passage 48, which as noted, connects withthe induction passage 12 posteriorly ofthe throttle 16. A first valvedevice 72 is disposed in conduit 70 for controlling the amount ofmanifold vacuum transmitted to the diaphragm 26. Valve device 72includes a member 74 slidably disposed in casing 76 and which member issuitably articulated to the thermostatically controlled lever 66. Thus,when the engine is cold the valve will be in the position shown inFigure l transmitting the maximum amount of manifold vacuum available inline 71 to the diaphragm 26. As the engine warms lever 66 will rotate ina counterclockwise direction moving the member 74 to a positionmodulating or gradually cutting olf they amount of manifold vacuumsuperimposed on the diaphragm 26. Device 72 modulates the vacuum forceby providing the member 74 with a suitably tapered portion 78 disposedbetween lands 80 and 82. Land 80 has a passage -84 therethrough fortransmitting the vacuum force to diaphragm 26. utilized to reduce thevacuum force available to act on the diaphragm and in this way seive asan orifice in line 70.

An additional valveV device 90, in parallel with valve lf desired,passage 84 may be" 72, is disposed in the manifold vacuum circuit and isadapted to provide Vadditional manifold vacuum during the crankingoperation of the engine under whichcondition a particularly richstarting mixture is desired. Device 90 likewise includes a member 92slidably disposed within casing 94 and which also includes a taperedsection 96 for metering the manifold vacuum ilow to the diaphragm ininverse proportion to engine temperature. Valve device 90 also hasassociated in series therewith a ball check valve 100 which upon thestarting Vof the engineris adapted to cut off the manifold vacuum flowthrough the branch circuit 162. Thus during cranking oftheengine valvedevices' 72 and 90 are each trans'- mitting'a manifold vacuum force totheV diaphragm 26.

As -soon as the engine begins to run, however, the crankingmodulatingsignal is cut off and manifol-d vacuum modulation takes place onlythrough valve 72. Y

In theevent a warm engine is re-started thegsliding members 74 and 92will be in a position to modulate.. the manifold vacuum to supplementventuri vacuum or toeliminate theV manifold vacuum force entirelyvdependent on the residual engine warmth. The valve devices 72 andA 90-are shown in their cold running positions.v

As noted with increasing engine temperatures the sliding members 74and92`are gradually shifted to the left, as viewed'in Figure l, bythermostatically controlled lever 66to reduce and ultimately eliminatethe 'force of manij.

fold vacuum on4 diaphragm 26.

In orderv to cut off the flow of fuel in the cylinder fuelsupplyingconduit 30 under'certaindecelerating condi;

Vto the cylinder supply lines 120.

member 112 `disposed on top of a 'fuel distributing manifold or spider114. As best seen in Figure 2 the fuel manifold comprises a casinghaving a boss 116 depending therefrom and to which is suitably connectedfuel conduit 30. The manifold casing 114 also includes a plurality ofcircumferentially spacedV radial bosses 118 each of which is connectedto a fuel line 120 leading to an individual cylinder of the engine.Under normal operating I conditions the metered fuel from valve 24enters the fuel manifold through boss 116 Vand is equally distributedto` upper position so as to move the metering valve 134,

out of flow restricting engagement with fuel passage 122.

While armature k13:0 may be held in its upper or normal restrictingposition by means such as a spring, the present device avoids thenecessity of such means and instead utilizes the pressure of fuel inpassages 122 and 124 f which acts against the tapered end 136 of thevalve as well as the tapered surface 140 of the armature to retain thelatter in its retracted position. It is apparent that by using fluidpressure to retract the armature Va simplied and'cheaper type structureresults.

The .solenoid 112` is actually mounted on manifold V114 by a pluralityof studs `142 which extend through the manifold intermediate radialpassages 126.v Studs 142v thread in openings 144 ina ylower end plate146 which is peripherally relieved at 148 to provide an annular lip 15).Solenoid casing 152 ris bent radially inwardly at its respective endsyto clampinglyl engage end plates 146 and 154.V Lower end plate 146includes an upstanding boss 156 tightly surrounding which is an armaturesupporting` End plate 146 is centrally relieved at 164 to receiveV aboss166 formed on fuel,manifold` 114., An yannular recess v168 surroundsboss 166 and receivesaseal 170 to'. i prevent the leakage of fuelbetween the solenoid and fuel manifold.

v The control of solenoid valve 130--134 is through .theV

combined effects ofa throttle controlled switch 172 and The throttlecontrolled switch 172 may beof. any co'n-H venient type and inasmuch asit does not, per se,con`v stitute `the subject matter of the presentinvention, is not -shown in detail.

tions afuelrcut-otf device indicatedgenerally at'110 'isprovided.This'deviceincludes a solenoid actuatedvalvel wereQprovided` to correcttherefore thev provision of a throttle controlled; switch only foractuating the solenoid 112,would result in frequentpengine stallingsince the throttle might remain closed until the engine had passed nwell below the speed where fuel was passing unburned through theengine.l Toavoid this situation the vadditional switch 174 is providedand which switch is adapted' to be closed above a certain engine speed:Here againA the engine speed" responsive switch mechanism 174 is Y notshown infdetail since any well known type ofspeed switchV mayberutilized .to perform the intended function.

For instance, switch 174mayV be operatedk by'a ily-ball governor,generator voltage, etc;

The essential requirement of switch 172is thatit be closed onlyV whenthe throttle is closed as will be Athe case when the vengine is-decelerating `under conditions wasteful of fuel. Unless, however,means.

Engine speed switch 174 may be adjusted to open at speeds below 3()miles per hour interrupting the ow of current to the solenoid 112irregardless of the fact that the throttle control switch 172 might beclosed and thereby insuring that the `fuel cut-olf mechanism willfunction no longer than necessary.

Power source 176 is connected to the speed control switch 174 through alead 178, the speed switch to the throttle control switch through a lead180 and the throttle control switch to the solenoid controlled valvethrough a lead 182 with the solenoid being grounded through lead 184.

The operation of the `deceleration cut-off device is briefly as follows:with the throttle valve 16 closed and the engine operating above a givenminimum speed the solenoid valve 112 will interrupt the ilow of fuelfrom the fuel manifold 114 until such time as the throttle is againopened or the engine speed drops below a given value as described.

We claim: v

l. A fuel injection system for an internal combustio engine comprisingan air induction passage, a venturi formed in said passage, a throttlevalve in said induction passage posterior to said venturi, a source offuel under pressure, conduit means communicating said fuel source withthe cylinders of the engine, a valve disposed in said conduit means formetering the quantity of fuel supplied to said cylinder, a device forcontrolling said valve, conduit means connecting said valve controldevice with said venturi to actuate said device in accordance with themass of air owing through said venturi, a valve device disposed in saidconduit means intermediate the metering valve and cylinders forinterrupting the flow of fuel, said va'lve device comprising a solenoid,a throttle controlled switch and an engine speed responsive switch inseries with each other and with said solenoid, said valve deviceblocking the flow of fuel through said conduit means when said switchesare closed to energize the solenoid.

2. A fuel injection system for an internal combustion engine comprisingan air induction passage, a venturi formed in said passage, a throttlevalve in said induction passage posterior to said venturi, a source offuel under pressure, conduit means communicating said fuel source withthe cylinders of the engine, a valve disposed in said conduit means formetering the quantity of fuel supplied to said cylinder, a device forcontrolling said valve, conduit means connecting said valve controldevice with said venturi to actuate said device in accordance with themass of air flowing through said venturi, a valve device disposed insaid conduit means 'intermediate the metering valve and cylinders forinterrupting the ow of fuel, said valve device comprising a solenoid, athrottle controlled switch and an engine speed responsive switch inseries with each other and said solenoid, said valve device blocking theflow of fuel through said conduit means when said switches are closed toenergize the solenoid, a passage for bypassing air around the throttlewhen closed during idling, a valve in said bypass passage, andtemperature responsive means actuating the bypass valve to render thequantity of idle air inversely proportional to engine temperature.

3. A fuel injection system for an internal combustion engine comprisingan air induction passage, a venturi formed in said passage, a throttlevalve in said induction passage posterior to said venturi, a source offuel under pressure, conduit means communicating said fuel source withthe cylinders of the engine, a valve disposed in said conduit means formetering the quantity of fuel supplied to said cylinder, a device forcontrolling said valve, conduit means connecting said valve controldevice with said venturi to actuate said device in accordance with themass of air flowing through said venturi, a valve device disposed insaid conduit means intermediate the metering valve and cylinders forinterrupting the flow of fueLl, said valve device comprising a solenoid,a throttle controlled switch and a speed responsive switch in serieswith each other and said solenoid, said valve device blocking the flowof fuel through said conduit means when said switches are closed toenergize the solenoid, a passage for bypassing air around the throttlewhen closed during idling, a valve in said bypass passage,'a conduitcommunicating said control device with the induction passage posteriorlyof lthe throttle valve, valve means in said latter conduit formodulating the manifold vacuum acting on the cotnrol device, and enginetemperature responsive means operatively connected to the bypass valveand the valve means to render the llow through both inverselyproportional to engine temperature.

4. A fuel injection system as set forth in claim l in which said valvedevice includes an armature having a valve element formed thereon, saidarmature and element being responsive to the fuel pressure and normallyheld thereby in a position permitting the free flow of fuel through theconduit means.

5. A fuel injection system for an internal combustion engine comprisingan lair induction passage; a Venturi formed in said passage; a throttlevalve in said induction passage posterior to said venturi; a source offuel under pressure; conduit means communicating said fuel source withthe cylinders of the engine; a valve disposed in said conduit means formetering the quantity of fuel supplied to said cylinder; a diaphragmdevice for controlling the metering valve, a conduit connecting saiddiaphragm device with said venturi for controlling said valve inaccordance with the mass of air flowing through the venturi; a fueldistributor; said conduit means including a passage connecting themetering valve with said fuel distributor for delivering fuel to thedistributor, and a plurality of passages leading from said distributor,said passages respectively communicating with the individual cylindersof said engine; a chamber in said manifold communicating with saiddelivery passage and said plurality of passages, valve means in saidchamber adapted to cut olf the ow of fuel through said manifold, saidvalve being responsive to the pressure of the fuel flowing through saiddistributor and normally moved thereby to a position permittinguninterrupted fuel flow to the passages, solenoid means adapted whenenergized to shift said valve to a position blocking the flow of fuelthrough the manifold, a source of power for energizing said solenoid, athrottle actuated switch and an engine speed responsive switch connectedin series with said power source and solenoid, said switches beingadapted to energize said solenoid during throttle-closed deceleration ofsaid vehicle.

6. A fuel injection system for an internal combustion engine `as setforth in claim 5 in which said solenoid includes an armature operativelyconnected to the valve means, said armature having a surface exposed tothe fuel pressure in said chamber for moving the valve means to permitthe flow of fuel through the distributor.

No references cited.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION E +G 1, No.,2,899,951 I Elmer Olson et el.

August 18, 1959 It is hereby certified that error appears in theprin-ted specification of the above numbered patent requiringcorrect-ion and that Jche said Letters Pai-,enrl should read ascorrected below.

` Column l, lille` 38, for "ln" read i-K if' .m5 @011mm g, 1in@ lo, #for"Derwood" read Dermozid nu; line 4l, for "comprisc-:fn read \Acompromise f1-o Signed and sealed this' 31st day of' Mey 1960.,

(SEAL) Attest:

KARL Iig AXLINE Attesting OfceiI ROBERT C. WATSON Commissioner ofPatents

